Is someone able to advise please - the zinnias I grew last year from seed, in coir jiffys were leggy with brown blotches on the leaves. Very different to previous years. Please see pics attached for comparison Is someone able to tell me why the brown marks have occurred before I start sowing again soon. Thank you!!

I noticed black sooty spots on the leaves of my Curry Leaf Tree (Murraya koenigii.) The underside of the leaves has caramel brown tiny bugs. This plant was inside and I never saw such a pest on any other of my plants. I immediately took it outside for cooler night air, sprayed it with a spray pyrethrin solution, and waited. The leaves now appear to be dropping off, but I don't notice any new top growth, despite watering and fertilizing. Did this pest kill this plant? It has been two weeks or more.How long should I wait until new healthy growth appears? The photo is one similar to my plant in its healthy stage, for identification purposes.